Online Urbanism: Interest-based Subcultures as Drivers of Informal Learning in an Online Community

Online communities continue to be an important resource for informal learning. Although many facets of online learning communities have been studied, we have limited understanding of how such communities grow over time to productively engage a large number of learners. In this paper we present a study of a large online community called Scratch which was created to help users learn software programming. We analyzed 5 years of data consisting of 1 million users and their 1.9 million projects. Examination of interactional patterns among highly active members of the community uncovered a markedly temporal dimension to participation. As membership of the Scratch online community grew over time, interest-based subcultures started to emerge. This pattern was uncovered even when clustering was based solely on social network of members. This process, which closely resembles urbanism or the growth of physically populated areas, allowed new members to combine their interests with programming.